Organo-aluminoxanes have been found to be useful in a wide variety of chemical processes. For example, metallocene-organo-aluminoxane-catalysts, which can be formed by reacting certain metallocenes with certain organo-aluminoxanes, have been used to polymerize olefins. One of the earliest patents containing such a disclosure is U.S. Pat. No. 3,242,099 (the entire disclosure of which is hereby incorporated by reference).
Such metallocene-organo-aluminoxane-catalysts have been used to polymerize olefins using solution polymerization technology. Since such metallocene-organo-aluminoxane-catalysts are soluble in the solution polymerization medium, it has been generally observed that the resulting polymer has a low bulk density, as well as, other undesirable qualities.
Attempts to use such metallocene-organo-aluminoxane-catalysts to polymerize olefins using slurry polymerization technology have not been satisfactory. In slurry polymerization, the polymerization conditions are selected so that the desired polymer forms as discrete particles that are insoluble, or only sightly soluble, in the slurry polymerization medium, which is usually an aliphatic hydrocarbon. It has been observed that when such slurry polymerizations are carried out using such metallocene-organo-aluminoxane-catalysts, the desired polymer coats the interior surface of the slurry polymerization vessel. This coating of the slurry polymerization vessel's interior surface is detrimental. This is because such coating adversely effects the heat transfer from the slurry polymerization vessel. Additionally, such coating results in the need for periodic, if not continuous, cleaning of the slurry polymerization vessel, in order to prevent such vessel from fouling.
It is known that heterogeneous catalysts can be useful in slurry polymerizations. Heterogeneous catalysts are catalysts that are not soluble, or only slightly soluble, in the polymerization medium.
It is known that a solid form of organo-aluminoxane can be obtained by mixing an organo-aluminoxane solution with a counter solvent; however, this solid, when used as part of a heterogeneous catalyst, has been found to cause fouling in a slurry polymerization vessel. Even when a counter solvent is used to precipitate the organo-aluminoxane onto an hydrocarbon-insoluble-particulate-carrier, fouling is still a problem during slurry polymerizations.
Consequently, processes to produce organo-aluminum compositions, which are useful in producing heterogeneous catalysts that can be used in slurry polymerizations without fouling the polymerization vessel, are greatly needed. Additionally, since metallocene-organo-aluminoxane catalysts are expensive to produce, processes that reduce the cost of producing these catalyst, or processes that increase to usefulness of these catalysts, are desired.